Epilepsy and screaming

Topic:

I have son who is now 4 and half years old, on therapy almoust 2 years, takes Convulex and Frisium,seizure type atipical absence,
As far as we can see, he doesn't have seizures lately.

The thing that I am writting for is that he screams and screams alot. He has development delays, his neurologist says he is PDD.
He started to scream when he was 7 months old, at that time we did out first EEG and showed irregular acitivity but no therapy until we saw actual seizures.

Could his screaming be related to his epilepsy in any way? I undestand that he screams when he can't speak but also when he screams he looks different and it is really hard to reach him?!